JP6535099B2 - Image reading apparatus, image reading method and image reading program - Google Patents

Description

  The present invention relates to an image reading apparatus, an image reading method, and an image reading program.

  There are various types of image reading devices that read an image of a reading medium such as a document. For example, an "overhead type image reader" which reads a reading medium from above in the vertical direction is known.

  Moreover, in recent years, there is a demand for electronic data conversion of a binding medium such as a book. For example, an overhead image reading apparatus that converts a book into electronic data reads each page of the spread of the book from above the spread surface in the vertical direction. In the following, a binding medium in a spread state may be referred to as a "spread medium".

Unexamined-Japanese-Patent No. 08-242347 gazette JP 09-149207 A

  For overhead reader users, it is generally desirable for the overhead reader to be as small as possible for reasons of installation space and the like. For this reason, in an overhead reader, the object-image distance is usually suppressed to about 300 to 400 mm, and it is difficult to take a large object-image distance. Generally, the depth of field of an overhead reader is often smaller because the depth of field decreases as the object image distance decreases.

  On the other hand, when the book is placed in a spread state on the placement surface, the book may be placed in a state where the center of the page is raised relative to the placement surface when the thickness of the book is large, etc. is there. For this reason, in the spread surface of the book, the height difference between the height of the "node" with respect to the placement surface and the height near the center of the page with respect to the placement surface may be large. Further, in the spread surface of the book, the height difference between the height of the “small edge” with respect to the placement surface and the height near the center of the page with respect to the placement surface may be large.

  As described above, since the depth of field of the overhead reader is often small, when the overhead reader reads the facing surface of a book having a large thickness, the height difference between the facing surfaces indicates the depth of field. May be exceeded. For this reason, in the image read by the overhead reader, an image of a portion beyond the depth of field may be blurred and blurred, which may make it difficult to determine characters and the like.

  The disclosed technology has been made in view of the above point, and aims to acquire a clear image.

  In an aspect of the disclosure, the image reading apparatus includes a detection unit, a determination unit, a reading unit, and a combining unit. The detection unit detects an elevation difference in the spread surface of the binding medium placed on the placement surface. The determination unit determines whether the height difference is within a predetermined depth of field. When the height difference is within the predetermined depth of field based on the determination result of the determination unit, the reading unit reads the image with the entire area of the spread area as the in-focus area once. While reading is performed, when the height difference exceeds the predetermined depth of field, multiple reading is performed to read a plurality of images having different in-focus areas on the spread surface. The combining unit combines the in-focus areas with each other in the plurality of images obtained by the plurality of readings.

  According to the aspect of the disclosure, a clear image can be obtained.

FIG. 1 is a schematic view (perspective view) of the image reading apparatus of the first embodiment. FIG. 2 is a schematic view (front view) of the image reading apparatus of the first embodiment. FIG. 3 is a schematic view (side view) of the image reading apparatus of the first embodiment. FIG. 4 is a schematic view (plan view) of the image reading apparatus of the first embodiment. FIG. 5 is a schematic view (side view) of the image reading apparatus of the first embodiment. FIG. 6 is a schematic view (plan view) of the image reading apparatus of the first embodiment. FIG. 7 is a diagram illustrating an example of a reading area of the image reading apparatus according to the first embodiment. FIG. 8 is a diagram illustrating an example of a reading area of the image reading apparatus according to the first embodiment. FIG. 9 is a view showing an example of the positional relationship between the reading line and the linear laser light in the first embodiment. FIG. 10 is a diagram showing an example of the positional relationship between the reading line and the linear laser light in the first embodiment. FIG. 11 is a block diagram showing the configuration of the image reading apparatus of the first embodiment. FIG. 12 is a diagram illustrating an example of the calibration operation of the first embodiment. FIG. 13 is a diagram illustrating an example of parameters corresponding to the reference position according to the first embodiment. FIG. 14 is a flowchart illustrating an example of the height difference detection process according to the first embodiment. FIG. 15 is a flowchart illustrating an example of the height difference detection process according to the first embodiment. FIG. 16 is a diagram showing an outline of a method of calculating three-dimensional data according to the first embodiment. FIG. 17 is a diagram for explaining the operation of the image reading apparatus according to the first embodiment. FIG. 18 is a diagram for explaining the operation of the image reading apparatus according to the first embodiment. FIG. 19 is a diagram for explaining the operation of the image reading apparatus according to the first embodiment. FIG. 20 is a diagram for explaining the operation of the image reading apparatus according to the first embodiment. FIG. 21 is a diagram for explaining the operation of the image reading apparatus according to the first embodiment. FIG. 22 is a diagram for explaining the operation of the image reading apparatus according to the first embodiment. FIG. 23 is a diagram for explaining the operation of the image reading apparatus according to the first embodiment. FIG. 24 is a flowchart illustrating an example of processing of the image reading apparatus according to the first embodiment. FIG. 25 is a diagram for explaining the operation of the image reading apparatus according to the second embodiment. FIG. 26 is a schematic view (perspective view) of the image reading apparatus of the third embodiment. FIG. 27 is a diagram for explaining the operation of the image reading apparatus according to the third embodiment. FIG. 28 is a diagram for explaining the operation of the image reading apparatus of the third embodiment. FIG. 29 is a schematic view (perspective view) of the image reading apparatus of the fourth embodiment. FIG. 30 is a diagram for explaining the operation of the image reading apparatus according to the fourth embodiment. FIG. 31 is a diagram for explaining the operation of the image reading apparatus according to the fourth embodiment.

  Hereinafter, embodiments of an image reading apparatus, an image reading method, and an image reading program disclosed in the present application will be described with reference to the drawings. The present invention is not limited by the following examples. Further, in the respective embodiments, the same structural members, the configurations having the same functions, and the steps for performing the same processing are denoted by the same reference numerals, and overlapping descriptions will be omitted.

Example 1
<Structure of Image Reading Device>
1 to 6 are schematic views of the image reading apparatus of the first embodiment. 1 is a perspective view, FIG. 2 is a front view, FIGS. 3 and 5 are side views, and FIGS. 4 and 6 are plan views. FIG. 3 and FIG. 4 correspond, and FIG. 5 and FIG. 6 correspond. 7 and 8 are diagrams showing an example of a reading area of the image reading apparatus of the first embodiment. Hereinafter, in each drawing, the width direction of the image reading apparatus 1 is “X direction”, the depth direction orthogonal to the width direction with the horizontal direction is “Y direction”, and the vertical direction orthogonal to the width direction and the depth direction is “Z direction” And illustrated.

  The image reading apparatus 1 of the first embodiment is used, for example, to read an image of a spread medium SM formed by binding a plurality of paper media at a binding unit. When the image reading device 1 is used to read an image of the spread medium SM, as shown in FIGS. 7 and 8, the first spread surface P1 of the spread medium SM and the second spread surface P2 are individually separated. The image data of the entire facing surfaces P1 and P2 is acquired by combining the respective read data corresponding to the facing surfaces P1 and P2. Hereinafter, as an example, a case where the image reading apparatus 1 is used to read an image of the spread medium SM will be described. In the following, in the spread medium SM, the opening direction is the width direction (X direction), and the extending direction of the binding portion orthogonal to the opening direction in the opening direction is orthogonal to the depth direction (Y direction), width direction, and depth direction Let the thickness direction be the vertical direction (Z direction).

  As shown in FIGS. 1 to 6, the image reading apparatus 1 includes a mounting table 2, an arm 3, a first support 4, a second support 5, a first reading unit 6, and a second reading unit. 7 and illumination 8.

  The mounting table 2 has a mounting table main body portion 21, a first mounting portion 22, and a second mounting portion 23, and the spread medium SM is mounted on the mounting table 2.

  The mounting table main body portion 21 is a portion in contact with the installation surface of the image reading apparatus 1, and the first mounting portion 22 and the second mounting portion 23 are mutually different in the width direction with respect to the mounting table main body portion 21. Be placed adjacent to each other. The first placement portion 22 and the second placement portion 23 have a flat plate shape, and the upper surface of the first placement portion 22 has a first placement surface 24 facing the first reading unit 6 in the vertical direction. The upper surface of the second placement unit 23 forms a second placement surface 25 facing the second reading unit 7 in the vertical direction. The first placement surface 24 and the second placement surface 25 are flat, and a part of the spread medium SM facing the spread surface P1 in the vertical direction is placed on the first placement surface 24, and the second placement surface 24 is placed on the second placement surface 24. In the placement surface 25, a part of the spread medium SM facing the spread surface P <b> 2 in the vertical direction is placed. That is, the first placement surface 24 and the second placement surface 25 are provided adjacent to each other in the width direction.

  Further, in the mounting table 2, the first mounting portion 22 and the second mounting portion 23 are arranged adjacent to each other with a gap therebetween. Therefore, when placing the spread medium SM on the mounting table 2, the binding portion of the spread medium SM can be inserted into the gap. Therefore, in the mounting table 2, the binding portion of the spread medium SM is located at a lower position (that is, the lower side in the vertical direction) than the both ends in the opening direction of the spread medium SM. Thus, the vicinity of the binding portion of the spread medium SM can be suppressed from rising in the upper side in the vertical direction, and positional deviation of the spread medium SM relative to the mounting table 2 can be suppressed.

  Each of the first placement surface 24 and the second placement surface 25 has identification areas DA1 and DA2 used when detecting the height of the spread medium SM in the vertical direction. The identification areas DA1 and DA2 are areas where the spread medium SM is placed (that is, areas other than the identification areas DA1 and DA2 of the placement surfaces 24 and 25 and hereinafter may be referred to as "placement areas"). Adjacent in the width direction. The identification area DA1 set on the first mounting surface 24 is a band-shaped area extending in the depth direction along the left end of the first mounting surface 24 and is set on the second mounting surface 25. The identified identification area DA2 is a band-like area extending in the depth direction along the right end of the second placement surface 25. With respect to the identification areas DA1 and DA2, as described later, a part of the linear laser light is irradiated in a state in which the spread medium SM is placed on the placement area.

  The arm 3 supports the reading units 6 and 7 to make the reading units 6 and 7 face the mounting table 2 in the vertical direction. The arm 3 has a flat plate shape, and is formed extending in the vertical direction from a portion on the back side in the depth direction of the mounting surface 24 or 25 in the mounting table main body 21.

  The first support portion 4 is formed to project leftward in the width direction from a portion on the upper side in the vertical direction of the arm 3 and supports the first reading unit 6. The second support portion 5 is formed to project from the upper portion in the vertical direction of the arm 3 to the right in the width direction, and supports the second reading unit 7.

  The first reading unit 6 is disposed to face the first placement surface 24 in the vertical direction, and is formed to extend from the first support portion 4 to the near side in the depth direction. The first reading unit 6 includes a first carrier 62 accommodating the first image reading unit 61 and the lens 66, a first carrier moving mechanism 63, a first mirror 64, and a first mirror rotation mechanism 65.

  The first image reading unit 61 reads a partial area of the spread medium SM placed on the placement table 2. The first image reading unit 61 is, for example, a line sensor formed of a plurality of light receiving elements linearly arranged along the width direction (X direction), and the surface on which the reading line IL1 parallel to the width direction is placed Form on 24. That is, the main scanning direction of the line sensor forming the reading line IL1 is the width direction (X direction). The first image reading unit 61 also has an optical axis L1.

  The first carrier 62 is supported movably in the depth direction, and the position of the first image reading unit 61 changes in the depth direction by moving the first carrier 62 in the depth direction. The optical path length to the first mirror 64 changes.

  The first carrier moving mechanism 63 reciprocates the first carrier 62 in the depth direction. For example, the first carrier moving mechanism 63 has an actuator (not shown), and reciprocates the first carrier 62 by the driving force from the actuator.

  The first mirror 64 is rotatably supported by the first reading unit 6 and changes the direction of the optical axis L1 of the first image reading unit 61. The first mirror 64 is rotatably supported around a rotation axis O1 parallel to the width direction. The first mirror 64 is disposed further to the back than the first carrier 62 in the depth direction, and is disposed further to the back than the mounting surface 24. The first mirror 64 turns the optical axis L1 in the depth direction back to the lower side in the vertical direction and to the near side in the depth direction. As the first mirror 64 rotates around the rotation axis O1, the optical axis L1 moves in the depth direction.

  The first mirror rotation mechanism 65 rotates the first mirror 64 in synchronization with the reciprocating movement of the first carrier 62 in the depth direction. For example, the first mirror rotation mechanism 65 has an actuator (not shown), and rotates the first mirror 64 by the driving force from the actuator.

  The movement of the first carrier 62 and the rotation of the first mirror 64 move the reading line IL1 of the first image reading unit 61 in the depth direction on the placement surface 24. That is, the sub-scanning direction of the line sensor forming the reading line IL1 is the depth direction (Y direction). By moving the reading line IL1 parallel to the width direction in the depth direction, a two-dimensional image on the first placement surface 24 can be read.

  The second reading unit 7 is disposed to face the second placement surface 25 in the vertical direction, and is formed to extend from the second support portion 5 to the near side in the depth direction. The second reading unit 7 includes a second carrier 72 accommodating the second image reading unit 71 and the lens 76, a second carrier moving mechanism 73, a second mirror 74, and a second mirror rotation mechanism 75.

  The second image reading unit 71 reads a partial area of the spread medium SM placed on the placement table 2. The second image reading unit 71 is, for example, a line sensor formed of a plurality of light receiving elements arrayed in a straight line along the width direction (X direction), and the surface on which the reading line IL2 parallel to the width direction is placed Form on 25. That is, the main scanning direction of the line sensor forming the reading line IL2 is the width direction (X direction). The second image reading unit 71 also has an optical axis L2.

  The second carrier 72 is supported movably in the depth direction, and the position of the second image reading unit 71 changes in the depth direction by moving the second carrier 72 in the depth direction. The optical path length to the second mirror 74 changes.

  The second carrier moving mechanism 73 reciprocates the second carrier 72 in the depth direction. For example, the second carrier moving mechanism 73 has an actuator (not shown), and reciprocates the second carrier 72 by the driving force from the actuator.

  The second mirror 74 is rotatably supported by the second reading unit 7 and changes the direction of the optical axis L2 of the second image reading unit 71. The second mirror 74 is rotatably supported around a rotation axis O2 parallel to the width direction. The second mirror 74 is disposed further to the back than the second carrier 72 in the depth direction, and is disposed further to the back than the mounting surface 25. The second mirror 74 turns the optical axis L2 in the depth direction back to the lower side in the vertical direction and to the near side in the depth direction. The optical axis L2 moves in the depth direction as the second mirror 74 rotates around the rotation axis O2.

  The second mirror rotation mechanism 75 rotates the second mirror 74 in synchronization with the reciprocating movement of the second carrier 72 in the depth direction. For example, the second mirror rotation mechanism 75 has an actuator (not shown), and rotates the second mirror 74 by the driving force from the actuator.

  The movement of the second carrier 72 and the rotation of the second mirror 74 move the reading line IL2 of the second image reading unit 71 in the depth direction on the placement surface 25. That is, the sub-scanning direction of the line sensor forming the reading line IL2 is the depth direction (Y direction). By moving the reading line IL2 parallel to the width direction in the depth direction, a two-dimensional image on the second placement surface 25 can be read.

  The illumination 8 applies light to the spread medium SM placed on the mounting table 2. The illumination 8 includes a first illumination 81 provided on the first reading unit 6 side, a second illumination 82 provided on the second reading unit 7 side, a first illumination rotation mechanism 83, and a second illumination rotation mechanism 84. Have.

  The first illumination 81 is rotatably supported around the rotation axis O1. The first illumination 81 is provided at both ends of the first reading unit 6 in the width direction. The irradiation range of the pair of first illuminations 81 is a strip extending in the width direction, and is larger than the reading area S1F of the first image reading unit 61 in the width direction. The first illumination rotation mechanism 83 rotates the pair of first illuminations 81. For example, the first illumination rotation mechanism 83 has an actuator (not shown), and rotates the pair of first illuminations 81 by the driving force from the actuator. The first illumination rotation mechanism 83 rotates the first illumination 81 such that the optical axis L1 moving in the depth direction by the rotation of the mirror 64 is always included in the illumination area LA1 of the first illumination 81.

  The second illumination 82 is rotatably supported around the rotation axis O2. In addition, the second illumination 82 is provided at both ends of the second reading unit 7 in the width direction. The irradiation range of the pair of second illuminations 82 is a strip extending in the width direction, and is larger than the reading area S2F of the second image reading unit 71 in the width direction. The second illumination rotation mechanism 84 rotates the pair of second illuminations 82. For example, the second illumination rotation mechanism 84 has an actuator (not shown), and rotates the pair of second illuminations 82 by the driving force from the actuator. The second illumination rotating mechanism 84 rotates the second illumination 82 such that the optical axis L2 moving in the depth direction by the rotation of the mirror 74 is always included in the illumination area LA2 of the second illumination 82.

  That is, the irradiation position of the illumination 8 with respect to the spread medium SM changes in synchronization with the positional change of the optical axes L1 and L2 with respect to the spread medium SM.

  Here, as shown in FIG. 7, the reading area S1F of the first image reading unit 61 includes a part of the reading area S2F of the second image reading unit 71, and one reading area S1F is included in the reading area S2F. Department is included. Further, as shown in FIG. 8, the reading area S1FA formed on the first placement surface 24 by the reading area S1F is larger than the first placement surface 24 in the width direction, and the second placement surface 25 is obtained by the reading area S2F. The reading area S2FA formed on the upper side is larger than the second mounting surface 25 in the width direction. The reading area S1FA is a rectangular horizontal surface on the first placement surface 24, and the reading area S2FA is a rectangular horizontal surface on the second placement surface 25. Furthermore, in the width direction, the end on the second mounting surface 25 side of the reading area S1FA is located closer to the second mounting surface 25 than the center of the mounting table 2, and the first mounting surface 24 of the reading area S2FA. The end on the side is positioned closer to the first mounting surface 24 than the center of the mounting table 2. That is, in the width direction, an overlapping area S0FA in which a part of the reading area S1FA and a part of the reading area S2FA overlap with each other is formed in the vicinity of the center of the mounting table 2. Therefore, the image read by the first image reading unit 61 and the image read by the second image reading unit 71 include mutually overlapping images.

  The first reading unit 6 further includes a first linear light irradiation unit 211, a first irradiation unit rotation mechanism 221, and a first linear light imaging camera 231.

  The first linear light irradiation unit 211 spreads the spread medium SM placed on the first placement surface 24 in order to irradiate the first placement surface 24 with the linear laser light BF1 parallel to the width direction. The surface P1 is irradiated with the linear laser light BF1. The first linear light emitting unit 211 is rotatably supported around the rotation axis O3 parallel to the width direction with respect to the first reading unit 6. The first linear light emitting unit 211 is disposed on the back side of the mounting surface 24 in the depth direction, and is disposed on the back side of the first mirror 64. The first linear light irradiation unit 211 moves the linear laser beam BF1 in the depth direction by rotating around the rotation axis O3.

  The first irradiating unit rotating mechanism 221 rotates the first linear light irradiating unit 211. For example, the first irradiation unit rotation mechanism 221 has an actuator (not shown), and rotates the first linear light irradiation unit 211 by the driving force from the actuator.

  The first linear light imaging camera 231 continuously images the reading area SF1A including the linear laser light BF1 asynchronously with the movement of the linear laser light BF1. The first linear light imaging camera 231 has an area sensor formed of a plurality of imaging elements arranged two-dimensionally in both the width direction (X direction) and the depth direction (Y direction). The first linear light imaging camera 231 is disposed near the end on the front side of the first reading unit 6 in the depth direction, and captures the entire surface of the spread surface P1 of the spread medium SM on the first placement surface 24 It is disposed on the lower surface side of the first reading unit 6 as much as possible.

  The second reading unit 7 further includes a second linear light irradiation unit 212, a second irradiation unit rotation mechanism 222, and a second linear light imaging camera 232.

  The second linear light irradiation unit 212 spreads the spread medium SM placed on the second placement surface 25 in order to irradiate the second placement surface 25 with the linear laser light BF2 parallel to the width direction. The surface P2 is to be irradiated with the linear laser beam BF2. The second linear light emitting unit 212 is rotatably supported by the second reading unit 7 around a rotation axis O4 parallel to the width direction. The second linear light emitting unit 212 is disposed on the back side of the mounting surface 25 in the depth direction, and is disposed on the rear side of the second mirror 74. The second linear light irradiation unit 212 moves the linear laser beam BF2 in the depth direction by rotating around the rotation axis O4.

  The second irradiation unit rotation mechanism 222 rotates the second linear light irradiation unit 212. For example, the second irradiation unit rotation mechanism 222 has an actuator (not shown), and rotates the second linear light irradiation unit 212 by the driving force from the actuator.

  The second linear light imaging camera 232 continuously images the reading area SF2A in a state including the linear laser light BF2 asynchronously with the movement of the linear laser light BF2. The second linear light imaging camera 232 has an area sensor formed of a plurality of imaging elements arranged two-dimensionally in both the width direction (X direction) and the depth direction (Y direction). The second linear light imaging camera 232 is disposed near the end on the front side of the second reading unit 7 in the depth direction, and captures the entire surface of the spread surface P2 of the spread medium SM on the second placement surface 25 It is disposed on the lower surface side of the second reading unit 7 as much as possible.

  Here, the positional relationship between the reading lines IL1 and IL2 and the linear laser beams BF1 and BF2 is, for example, as follows. FIGS. 9 and 10 are diagrams showing an example of the positional relationship between the reading line and the linear laser light in the first embodiment.

  As shown in FIGS. 9 and 10, the reading lines IL1 and IL2 and the linear laser beams BF1 and BF2 move in the depth direction so as not to overlap with each other. Further, in the width direction, the linear laser beam BF1 and the linear laser beam BF2 do not overlap.

  For example, as shown in FIG. 9, in the depth direction, the linear laser beam BF1 is always located at the back side of the reading line IL1, and the linear laser beam BF2 is always located at the back side of the reading line IL2. For example, as shown in FIG. 10, in the depth direction, the linear laser beam BF1 is always located on the front side of the reading line IL1, and the linear laser beam BF2 is always located on the front side of the reading line IL2. 9 and 10, the distance between the linear laser beam BF1 and the reading line IL1 is kept constant in the depth direction, and the distance between the linear laser beam BF2 and the reading line IL2 is kept constant. Get down.

<Configuration of Image Reading Device>
FIG. 11 is a block diagram showing the configuration of the image reading apparatus of the first embodiment. In FIG. 11, the image reading apparatus 1 includes a first reading unit 6, a second reading unit 7, and a control unit 10. Each part in control unit 10 shows each function of control unit 10. The control unit 10 has, for example, a processor and a memory as hardware components. Each function of the control unit 10 is realized by the processor and the memory. Examples of the processor include a central processing unit (CPU), a digital signal processor (DSP), and a field programmable gate array (FPGA). The control unit 10 may also have a large scale integrated circuit (LSI) that includes a processor and peripheral circuits. Examples of the memory include RAM such as SDRAM, ROM, flash memory and the like. The control unit 10 is provided, for example, inside the mounting table main body 21.

  The control unit 10 includes an image reading control unit 101, a lighting control unit 102, a first mechanism control unit 103, an image processing unit 105, a storage unit 106, and a communication unit 107. The image processing unit 105 includes a combining unit 170. The communication unit 107 is connected to an external device 300 external to the image reading apparatus 1. The external device 300 is, for example, a personal computer. The control unit 10 further includes a linear light irradiation control unit 108, a linear light imaging control unit 109, a second mechanism control unit 110, and a calibration unit 120. Further, the control unit 10 includes an elevation difference detection unit 130, an elevation difference determination unit 140, a depth of field setting unit 150, and a reading number determination unit 160.

  The image reading control unit 101 controls reading start timing, reading end timing, exposure time, exposure timing, and the like of the first image reading unit 61 and the second image reading unit 71.

  The illumination control unit 102 controls the lighting timing, the lighting-off timing, the light amount and the like of the first lighting 81 and the second lighting 82.

  The first mechanism control unit 103 includes a first carrier moving mechanism 63, a second carrier moving mechanism 73, a first mirror rotation mechanism 65, a second mirror rotation mechanism 75, a first illumination rotation mechanism 83, and a second mechanism. The illumination rotation mechanism 84 is controlled. The first mechanism control unit 103 operates actuators of each mechanism to move the first carrier 62 and the second carrier 72, rotate the first mirror 64 and the second mirror 74, and operate the first illumination 81 and the first The rotational operations of the two lights 82 are controlled in synchronization with each other.

  The image processing unit 105 generates data of an image of the entire area of the reading area S1FA (hereinafter may be referred to as “first read data”) from the signal representing the image read by the first image reading unit 61. . Further, from the signal representing the image read by the second image reading unit 71, the image processing unit 105 may use data of an image of the entire reading area S2FA (hereinafter may be referred to as “second read data”). Generate The combining unit 170 combines the first read data and the second read data, and image data corresponding to the entire area of the spread faces P1 and P2 of the spread medium SM (hereinafter may be referred to as “spread face image data”) Generate The first read data and the second read data include mutually overlapping data (that is, data of an image in the overlapping area S0FA). Therefore, the combining unit 170 combines one data of the first read data or the second read data with the remaining data after removing the duplicate data from the other data, based on the overlapping area S0FA. Generate facing surface image data.

  The storage unit 106 stores first read data, second read data, and spread plane image data. Further, the storage unit 106 stores parameters obtained by the calibration unit 120.

  The communication unit 107 can output the first read data, the second read data, and the spread area image data stored in the storage unit 106 to the external device 300.

  The linear light irradiation control unit 108 controls the lighting timing, the extinguishing timing, the light amount, and the like of the first linear light irradiation unit 211 and the second linear light irradiation unit 212.

  The linear light imaging control unit 109 controls imaging start timing, imaging timing, exposure time, exposure timing, and the like of the first linear light imaging camera 231 and the second linear light imaging camera 232.

  The second mechanism control unit 110 operates the actuators of the first irradiating unit rotating mechanism 221 and the second irradiating unit rotating mechanism 222 to control the rotating operation of the first irradiating unit rotating mechanism 221 and the second irradiating unit rotating mechanism 222. .

  The calibration unit 120 is for the first linear light irradiation unit 211 and the first linear light with respect to the plurality of reference positions 1 to n (see FIGS. 12 and 13) set in the identification areas DA1 and DA2. A parameter based on the positional relationship with the imaging camera 231 and a parameter based on the positional relationship between the second linear light irradiation unit 212 and the second linear light imaging camera 232 are set and stored in the storage unit 106.

  FIG. 12 is a diagram showing an example of the calibration operation of the first embodiment, and FIG. 13 is a diagram showing an example of parameters corresponding to the reference position of the first embodiment. Although FIG. 12 shows the calibration operation in the second reading unit 7 as an example, the calibration operation in the first reading unit 6 is also similar to the calibration operation in the second reading unit 7.

  In FIG. 12, the second linear light irradiation unit 212 generates linear laser beams B1, B2, and B3 to Bn with respect to the second placement surface 25 including the identification area DA2 from the far side to the near side in the depth direction. Irradiate sequentially while moving to. The second linear light imaging camera 232 sequentially images the second mounting surface 25 to which the linear laser beams B1, B2, B3 to Bn are sequentially irradiated, and the linear laser beams B1, B2, B3 to Bn Image data including a captured image of Below, the image data containing the captured image of linear laser beam B may be called "linear laser beam image data."

  As illustrated in FIG. 13, the calibration unit 120 sets a parameter 1 for three-dimensional coordinate calculation with respect to a reference position 1 indicated by the linear laser beam B1 irradiated to the identification area DA2. Similarly, the calibration unit 120 sets parameters 2 and 3 to 3 for three-dimensional coordinate calculation to the reference positions 2 and 3 to n indicated by each of the linear laser beams B2 and B3 to Bn. A well-known triangular distance measurement method is used to set parameters for three-dimensional coordinate calculation based on the positional relationship between the second linear light irradiation unit 212 and the second linear light imaging camera 232. The calibration unit 120 stores each of the parameters 1, 2, 3 to n in the storage unit 106 in association with each of the reference positions 1, 2, 3 to n. The parameters stored in the storage unit 106 are used as coefficients (a, b, c, d) of the plane equation used by the height difference detection unit 130.

  The height difference detection unit 130 detects the height difference DOE1 in the vertical direction on the spread surface P1 of the spread medium SM placed on the first placement surface 24 based on the linear laser light image data. Further, the height difference detection unit 130 detects the height difference DOE2 in the vertical direction on the spread surface P2 of the spread medium SM placed on the second placement surface 25 based on the linear laser light image data.

  The height difference determination unit 140 determines whether the height difference DOE1 detected by the height difference detection unit 130 is within the predetermined depth of field DOF1 of the first reading unit 6, and the determination result is an image reading control unit. 101, and output to the combining unit 170 and the reading number determining unit 160. Further, the height difference determination unit 140 determines whether the height difference DOE2 detected by the height difference detection unit 130 is within the predetermined depth of field DOF 2 of the second reading unit 7 and reads the determination result as an image. The information is output to the control unit 101, the combining unit 170, and the reading number determination unit 160. Generally, the size of the depth of field DOF1 is the same as the size of the depth of field DOF2.

  When the height difference DOE1 is within the depth of field DOF1, the image reading control unit 101 performs “single reading” that reads once the image on the entire surface of the spread plane P1 in one scan in the sub scanning direction. The reading unit 6 is made to perform. Therefore, when the height difference DOE1 is within the depth of field DOF1, the combining unit 170 acquires the first read data once. On the other hand, when the height difference DOE1 exceeds the depth of field DOF1, the image reading control unit 101 reads "multiple reading" reading the image on the entire surface of the spread plane P1 multiple times by multiple scans in the sub scanning direction. The first reading unit 6 is made to perform. Therefore, when the height difference DOE1 exceeds the depth of field DOF1, the combining unit 170 acquires the first read data a plurality of times.

  Further, when the height difference DOE 2 is within the depth of field DOF 2, the image reading control unit 101 reads “single reading” that reads the image on the entire surface of the spread plane P 2 once in one scan in the sub scanning direction. The second reading unit 7 is made to perform. Therefore, when the height difference DOE2 is within the depth of field DOF2, the combining unit 170 acquires the second read data once. On the other hand, when the height difference DOE 2 exceeds the depth of field DOF 2, the image reading control unit 101 reads “multiple reading” reading the image on the entire surface of the spread plane P 2 multiple times by multiple scans in the sub scanning direction. The second reading unit 7 is made to perform. Therefore, when the height difference DOE2 exceeds the depth of field DOF2, the combining unit 170 acquires the second read data a plurality of times.

  Then, when the height difference DOE1 exceeds the depth of field DOF1, the combining unit 170 combines the first read data acquired a plurality of times to generate final first read data. Further, when the height difference DOE2 exceeds the depth of field DOF2, the combining unit 170 combines the second read data acquired a plurality of times to generate the final second read data. Details of the synthesis in the synthesis unit 170 will be described later.

  The depth of field setting unit 150 sets the depth of field DOF 1 and DOF 2 in the height difference determination unit 140 according to the resolution desired by the user of the image reading device 1. A user can set a desired resolution in the image reading apparatus 1 using an input interface (not shown) of the image reading apparatus 1.

  When the height difference DOE1 exceeds the depth of field DOF1, the number-of-readings determining unit 160 determines the number of readings in multiple readings by the first reading unit 6, and outputs the determined number of readings to the image reading control unit 101. . Further, when the height difference DOE 2 exceeds the depth of field DOF 2, the reading number determination unit 160 determines the number of readings in the multiple reading by the second reading unit 7 and sends the determined reading number to the image reading control unit 101. Output. The image reading control unit 101 causes the first reading unit 6 and the second reading unit 7 to perform a plurality of readings with the number of readings determined by the number-of-readings determining unit 160. For example, the reading number determination unit 160 determines the minimum M that satisfies the condition of “DOF1 × MDODOE1 (M is an integer of 2 or more)” as the number of readings in the multiple reading in the first reading unit 6. Further, for example, the reading number determination unit 160 determines the minimum K that satisfies the condition of “DOF2 × K ≧ DOE2 (K is an integer of 2 or more)” as the number of readings in the multiple reading by the second reading unit 7.

<High / low difference detection processing>
14 and 15 are flowcharts illustrating an example of the height difference detection process according to the first embodiment. FIG. 14 shows a flowchart of image acquisition processing in height difference detection processing, and FIG. 15 shows a flowchart of three-dimensional data calculation processing in height difference detection processing.

  In step ST20 in FIG. 14, the linear light irradiation control unit 108 controls the first linear light irradiation unit 211 and the second linear light irradiation unit 212 to turn off the linear laser light, and the linear light is controlled. The imaging control unit 109 controls the first linear light imaging camera 231 and the second linear light imaging camera 232 to acquire an image of the spread medium SM. That is, the "image without laser beam" is acquired.

  Next, in step ST21, the linear light irradiation control unit 108 controls the first linear light irradiation unit 211 and the second linear light irradiation unit 212 to turn on the linear laser light.

  Next, in step ST22, the second mechanism control unit 110 controls the first irradiating unit rotating mechanism 221 and the second irradiating unit rotating mechanism 222 to control the first linear light irradiating unit 211 and the second linear light irradiating unit 212. By starting the rotation operation, the movement of the linear laser light is started.

  Next, in step ST23, the linear light imaging control unit 109 controls the first linear light imaging camera 231 and the second linear light imaging camera 232 in a state in which the linear laser light is turned on to open the spread. Start reading an image of the medium SM. That is, reading of the “image with laser beam” is started.

  Next, in step ST24, the linear light imaging control unit 109 determines whether the current frame is a new frame. When the current frame is not a new frame (step ST24: No), the linear light imaging control unit 109 repeats the determination of step ST24. On the other hand, when the current frame is a new frame (step ST24: Yes), the process proceeds to step ST25.

  In step ST25, the linear light imaging control unit 109 controls the first linear light imaging camera 231 and the second linear light imaging camera 232 to read an image with a laser beam.

  Next, in step ST26, the linear light irradiation control unit 108 determines whether the linear laser light has been moved from the irradiation start position to the irradiation end position. That is, the linear light irradiation control unit 108 determines whether or not the movement of the linear laser light has ended. When the movement of the linear laser light has not ended (step ST26: No), the process returns to step ST24. On the other hand, when the movement of the linear laser light ends (step ST26: Yes), the process proceeds to step ST27.

  Next, in step ST27, the linear light imaging control unit 109 controls the first linear light imaging camera 231 and the second linear light imaging camera 232 to end the reading of the image with laser light.

  Next, in step ST28, the linear light irradiation control unit 108 controls the first linear light irradiation unit 211 and the second linear light irradiation unit 212 to turn off the linear laser light.

  Thus, the image reading device 1 obtains an image without laser light and an image with laser light. The one laser light absent image acquired in step ST20 and the plurality of laser light present images acquired in step ST25 are stored in the storage unit 106.

  Next, in step ST30 of FIG. 15, the height difference detection unit 130 determines whether the image acquisition process illustrated in FIG. 14 has ended. When the image acquisition process shown in FIG. 14 is not completed (step ST30: No), the height difference detection unit 130 repeats the determination of step ST30. On the other hand, when the image acquisition process shown in FIG. 14 is completed (step ST30: Yes), the process proceeds to step ST31.

  In step ST31, the height difference detection unit 130 detects an image of linear laser light from the difference between the image without laser light and the image with laser light.

  Next, in step ST32, the height difference detection unit 130 specifies the current position of the linear laser light in the identification areas DA1 and DA2 from the image of the linear laser light detected in step ST31.

  Next, in step ST33, the height difference detection unit 130 uses the current position of the linear laser light specified in step ST32 and the parameters 1, 2, 3 to n stored in the storage unit 106 by the calibration unit 120. By calculating three-dimensional data (three-dimensional coordinates), the heights of the spread planes P1 and P2 at the current position of the linear laser light are estimated.

FIG. 16 is a diagram showing an outline of a method of calculating three-dimensional data according to the first embodiment. In FIG. 16, the elevation difference detection unit 130 can acquire the real space shape of the linear laser beam when detecting the image of the linear laser beam. Further, the height difference detection unit 130 can acquire laser coordinates (u _i , v _i ) indicating the current position of the linear laser light in the identification areas DA1 and DA2. The height difference detection unit 130 searches the reference position corresponding to the laser coordinates (u _i , v _i ) from the reference positions 1 to n stored in the storage unit 106, and matches the current position of the linear laser light The parameters (a, b, c, d) associated with the reference position to be acquired are acquired from the storage unit 106. The height difference detecting unit 130, to construct the obtained parameters (a, b, c, d ) by applying the well known plane equation the camera model as shown in FIG. 16, the laser coordinate (u _i, Three-dimensional coordinates (X _i , Y _i , Z _i ) corresponding to v _i ) are calculated. In three-dimensional coordinates (X _i , Y _i , Z _i ), Z _i is the height in the vertical direction with respect to the first placement surface 24 at a plurality of positions in the spread plane P1, and This corresponds to the height in the vertical direction with respect to the second mounting surface 25 at the position. The height difference detection unit 130 stores the sequentially calculated three-dimensional coordinates (X _i , Y _i , Z _i ) in the storage unit 106.

  In this manner, the height difference detection unit 130 determines the height of the irradiation position of the linear laser beam B on the spread surfaces P1 and P2 based on the parameters associated with the reference positions in the identification areas DA1 and DA2. By estimating, the height in the vertical direction with respect to the first mounting surface 24 at a plurality of positions in the spread surface P1, and in the vertical direction with respect to the second mounting surface 25 in a plurality of positions in the spread surface P2. Estimate the height. Then, the height difference detection unit 130 detects the difference between the maximum height and the minimum height among heights at a plurality of positions estimated with respect to the spread surface P1 as the height difference DOE1 in the spread surface P1. Further, the height difference detection unit 130 detects a difference between the maximum height and the minimum height among heights at a plurality of positions estimated with respect to the spread plane P2 as the height difference DOE2 in the spread plane P2. The height difference detection unit 130 stores the detected height differences DOE1 and DOE2 in the storage unit 106.

<Operation of Image Reading Device>
17 to 23 are diagrams for explaining the operation of the image reading apparatus according to the first embodiment. Here, since the operation on the first mounting surface 24 and the operation on the second mounting surface 25 are the same, the operation on the second mounting surface 25 will be described below. The description of the operation is omitted.

  As shown in FIGS. 17 and 18, the height difference determination unit 140 determines whether the height difference DOE2 in the facing surface P2 of the facing medium SM placed on the second placement surface 25 is within the depth of field DOF2. Determine if FIG. 17 shows the case where the height difference DOE2 is within the depth of field DOF2, and FIG. 18 shows the case where the height difference DOE2 exceeds the depth of field DOF2.

If the height difference DOE 2 exceeds the depth of field DOF 2, the reading number determination unit 160 determines the number of readings in multiple readings by the second reading unit 7. The number-of-reads determining unit 160 determines, for example, the minimum number of K satisfying the condition of “DOF 2 × KDODOE 2 (K is an integer of 2 or more)” as the number of times of reading in multiple readings by the second reading unit 7. The reading number K is output to the image reading control unit 101. Here, as an example, the number of times of reading is assumed to be determined twice (K = 2). When the number of readings determination unit 160 determines that the number of readings is two, as shown in FIGS. 19 (a1), (b1), and (c1), the height of half the height difference DOE2 is set. Determined as "division boundary DB". Further, based on the three-dimensional coordinates (X _i , Y _i , Z _i ) stored in storage unit 106, reading number determination unit 160 determines the position corresponding to the height of division boundary DB within spread surface P2 ( That is, positions B1 and B2 higher than the minimum height in the spread surface P2 from the minimum height by the division boundary DB are determined as "division boundary positions", and the calculated division boundary positions B1 and B2 are output to the image reading control unit 101.

  Therefore, as shown in FIG. 19A1, in the spread plane P2, the region from the division boundary DB to the depth of field DOF2 in the vertical direction is the in-focus region (that is, the region in focus) FA1. Further, as shown in FIG. 19 (b1), in the spread plane P2, the area from the division boundary DB to the depth of field DOF2 in the vertical direction is the focusing area FA2. The in-focus area FA1 and the in-focus area FA2 are in-focus areas different from each other in the spread plane P2.

Therefore, the image reading control unit 101 determines that the optical path length at the position SP1 (see FIG. 19A1) existing in the focusing area FA1 is in the state where the reading line IL2 is at the initial position PS at the first reading. The second carrier 72 is moved to be "L". The position of the second carrier 72 whose optical path length is “L” at the position SP1 is the reading start position of the second carrier 72 in the first reading. Based on the three-dimensional coordinates (X _i , Y _i , Z _i ) stored in the storage unit 106, the image reading control unit 101, for example, as shown in FIG. A position corresponding to the height h1 of "one half of the depth of field DOF2" is set as the position SP1. An example of the reading start position of the second carrier 72 in the first reading is shown in FIG. That is, the optical path length at the reading start position of the second carrier 72 in the first reading is “L = 11 + 12”.

  As shown in FIGS. 20 and 21, while the optical path length is kept constant at "L", the image reading control unit 101 opens the second image reading unit 71 while moving the second carrier 72 in the sub scanning direction. The image of plane P2 is read. For example, as shown in FIGS. 20 and 21, the sub-scanning direction in the first reading is the direction from the back side to the front side in the depth direction. An example of the reading end position of the second carrier 72 in the first reading is shown in FIG. That is, the optical path length at the reading end position of the second carrier 72 in the first reading is “L = 13 + 14”. When the second carrier 72 reaches the reading end position shown in FIG. 21, the reading line IL2 reaches the final position PE and the first reading is finished, and the first image of the entire spread surface P2 is obtained. Be

Next, the image reading control unit 101 determines that the optical path length at the position SP2 (see FIG. 19B1) existing in the focusing area FA2 is in a state where the reading line IL2 is at the final position PE at the second reading. The second carrier 72 is moved to be "L". The position of the second carrier 72 whose optical path length is “L” at the position SP2 is the reading start position of the second carrier 72 in the second reading. Based on the three-dimensional coordinates (X _i , Y _i , Z _i ) stored in the storage unit 106, the image reading control unit 101, for example, as shown in FIG. A position corresponding to the height h2 of "one half of the depth of field DOF2" is set as the position SP2. An example of the reading start position of the second carrier 72 in the second reading is shown in FIG. That is, the optical path length at the reading start position of the second carrier 72 in the second reading is “L = 15 + 16”. Here, l5 <l3, l6> l4, l3-l5 = l6-l4.

  As shown in FIGS. 22 and 23, while the optical path length is kept constant at “L”, the image reading control unit 101 spreads the second image reading unit 71 while moving the second carrier 72 in the sub scanning direction. The image of plane P2 is read. For example, as shown in FIGS. 22 and 23, the sub-scanning direction in the second reading is the direction from the near side to the far side in the depth direction. That is, in the second reading, the image reading control unit 101 moves the second carrier 72 in the direction opposite to the moving direction in the first reading. An example of the reading end position of the second carrier 72 in the second reading is shown in FIG. That is, the optical path length at the reading end position of the second carrier 72 in the second reading is “L = 17 + 18”. When the second carrier 72 reaches the reading end position shown in FIG. 23, the reading line IL2 returns to the initial position PS and the second reading is finished, and a second image of the entire surface of the facing surface P2 is obtained. .

  Here, the focusing range FA1 in the first reading is as shown in FIG. 19A1, and the focusing range FA2 in the second reading is as shown in FIG. 19B1. Therefore, in the first reading, as shown in FIG. 19A2, an image in focus at a position at a height higher than the division boundary DB can be obtained in the spread plane P2. FIG. 19A2 illustrates, as an example, a case where the right half of the spread plane P2 is the focusing area FA1. On the other hand, in the second reading, as shown in FIG. 19B, an image in focus at a position below the dividing boundary DB in the spread plane P2 is obtained. FIG. 19 (b 2) shows, as an example, the case where the left half of the spread plane P 2 is the focusing area FA 2. Therefore, by combining the right half of the image obtained in the first reading and the left half of the image obtained in the second reading, it is possible to obtain an image in focus on the entire spread surface P2. it can. Hereinafter, the image of the right half of the spread plane P2 may be referred to as the “right half image”, and the image of the left half of the spread plane P2 may be referred to as the “left half image”.

  However, while the light path length is set to “L” based on the position SP1 (see FIG. 19 (a1)) in the first reading, the position SP2 (see FIG. 19 (b1)) is referred to in the second reading. And the optical path length is set to “L”. Therefore, with regard to the magnification near the division boundary position B2 (that is, near the junction of the right half image and the left half image), as shown in FIGS. 19 (a2) and (b2), the magnification during the first reading MX is smaller than the magnification MY at the time of the second reading. Therefore, if the right half image in focus in the first reading and the left half image in focus in the second reading are simply combined, images having different magnifications will be combined.

  Therefore, the combining unit 170 performs magnification adjustment on the right half image and the left half image. That is, the right half image and the left half image are respectively scaled. For example, if the standard magnification is described as “Std”, the synthesizing unit 170 multiplies the right half image by “Std / MX” and multiplies the magnification of the right half image, as shown in FIGS. 19 (a2) and (c2). Change from MX to Std. Further, as illustrated in (b2) and (c2) of FIG. 19, the combining unit 170 multiplies the left half image by “Std / MY” and changes the magnification of the left half image from MY to Std. By such magnification adjustment, the magnifications of both the right half image and the left half image become the same at Std. Therefore, the combining unit 170 combines the right half image of the magnification Std and the left half image of the magnification Std, as shown in FIG. 19C, so that the entire surface of the spread plane P2 is in focus and spread Images of the same magnification are acquired on the entire surface P2.

  The magnification ratio MX can be calculated from the height difference between the position SP1 as a reference for setting the optical path length L and the division boundary position B2 as follows. Similarly, the magnification ratio MY can be calculated from the height difference between the position SP2 serving as a reference for setting the optical path length L and the division boundary position B2 as follows.

That is, at the position SP1 which is a reference of setting of the optical path length L, the magnification is "1.0". Therefore, if the height difference between the position SP1 and the division boundary position B2 is expressed as "d1", the following equation (1) holds, and the magnification MX can be calculated by the equation (2) obtained by modifying the equation (1) it can.
1.0: L = MX: (L + d1) (1)
MX = (L + d1) / L (2)

Similarly, at the position SP2 serving as a reference for setting the optical path length L, the magnification is "1.0". Therefore, if the height difference between the position SP2 and the division boundary position B2 is expressed as "d2", the following equation (3) holds, and the magnification MY can be calculated by the equation (4) obtained by modifying the equation (3) it can.
1.0: L = MY: (L + d2) (3)
MY = (L + d2) / L (4)

<Processing of Image Reading Device>
FIG. 24 is a flowchart illustrating an example of processing of the image reading apparatus according to the first embodiment. Here, since the processing for the first mounting surface 24 and the processing for the second mounting surface 25 are the same, the processing for the second mounting surface 25 will be described below, and the processing for the first mounting surface 24 will be described below. The description of the process is omitted.

  In step ST101 of FIG. 24, the height difference detection unit 130 detects the height difference DOE2 in the vertical direction on the spread surface P2 of the spread medium SM placed on the second placement surface 25.

  Next, in step ST103, the height difference determination unit 140 determines whether the height difference DOE2 is within the depth of field DOF2. The depth of field DOF 2 is set by the depth of field setting unit 150 according to the resolution desired by the user of the image reading device 1. When the height difference DOE2 is within the depth of field DOF2 (step S103: Yes), the process proceeds to step ST105. On the other hand, when the height difference DOE2 exceeds the depth of field DOF 2 (step S103: No), the process proceeds to step ST111.

  In step ST105, the reading number determining unit 160 determines the reading number K to be 1 (K = 1) since the elevation difference DOE2 is within the depth of field DOF2, and the determined reading number K is the image reading control unit Output to 101.

  Here, when the process proceeds to step ST107, since the height difference DOE2 is within the depth of field DOF2, the entire area of the facing surface P2 is the in-focus area. Therefore, in step ST107, the image reading control unit 101 causes the second carrier 72 so that the optical path length at any position in the spread plane P2 becomes “L” in a state where the reading line IL2 is at the initial position PS. Move That is, the image reading control unit 101 adjusts the optical path length.

  Next, in step ST109, the image reading control unit 101 causes the second image reading unit 71 to move the second carrier 72 in the sub-scanning direction while keeping the optical path length constant at "L", and displays an image of the spread plane P2. Make it read. The sub-scanning direction here is, for example, a direction from the back side to the front side in the depth direction. Then, when the reading line IL2 reaches the final position PE, the image reading control unit 101 ends the reading of the image on the facing surface P2.

  Therefore, when the height difference DOE2 is within the depth of field DOF2, when the reading line IL2 reaches the final position PE from the initial position PS, that is, when one sub-scan is completed, An image in which the entire surface is in focus can be obtained. Therefore, when the height difference DOE2 is within the depth of field DOF2 as in steps ST105 to ST109, the second image reading unit 71 reads the image with the entire area of the spread plane P2 as the in-focus area once. Read.

  On the other hand, when the process proceeds to step ST111, since the height difference DOE2 exceeds the depth of field DOF2, only a part of the spread plane P2 is in the in-focus area. Therefore, in step ST111, the reading number determining unit 160 determines the reading number K based on the height difference DOE2, and outputs the determined reading number K to the image reading control unit 101. The number of times of reading K determined in step ST111 is two or more.

  Next, in step ST113, the reading number determination unit 160 determines the division boundary DB of each reading in multiple reading based on the reading number K determined in step ST111.

  Next, in step ST115, the image reading control unit 101 resets the value of the counter k to an initial value "0".

  Next, in step ST117, the image reading control unit 101 increments the value of the counter k by "1".

  Next, in step ST119, the image reading control unit 101 causes the optical path length at a certain position in the in-focus area corresponding to the value of the counter k to be "L" in the spread plane P2. The second carrier 72 is moved. That is, the image reading control unit 101 adjusts the optical path length.

  Next, in step ST121, the image reading control unit 101 causes the second image reading unit 71 to move the second carrier 72 in the sub-scanning direction while keeping the optical path length constant at "L", and displays an image of the spread plane P2. Make it read.

  Next, in step ST123, the image reading control unit 101 determines whether the value of the counter k has reached the number of times of reading K or not. If the value of the counter k has not reached the number of times of reading K (step ST123: No), the process returns to step ST117. On the other hand, when the value of the counter k has reached the reading number K (step ST123: Yes), the process proceeds to step ST125.

  In step ST125, the combining unit 170 combines the image of the entire surface of the spread plane P2 read a plurality of times by the multiple reading as described above.

  As described above, in the first embodiment, the image reading device 1 includes the height difference detection unit 130, the height difference determination unit 140, the second image reading unit 71, and the combining unit 170. The height difference detection unit 130 detects the height difference DOE2 on the spread surface P2 of the spread medium SM placed on the placement surface 25. The height difference determination unit 140 determines whether the height difference DOE2 is within the depth of field DOF2. When the height difference DOE2 is within the depth of field DOF2, the second image reading unit 71 performs a single reading of reading an image in which the entire area of the facing surface P2 is the in-focus area. On the other hand, when the height difference DOE2 exceeds the depth of field DOF2, the second image reading unit 71 performs a plurality of readings for reading a plurality of images having different in-focus areas on the spread surface P2. The combining unit 170 combines the in-focus areas of the plurality of images obtained by the plurality of readings by the second image reading unit 71.

  By doing this, even if the height difference in the spread surface of the spread medium exceeds the depth of field, multiple reading of the image on the entire spread surface and composition of a plurality of focused images on the entire spread surface It is possible to obtain a clear image that was in focus. In addition, since the single reading is performed when the height difference in the spread surface is within the depth of field, an image is obtained as compared to the case where multiple reading is performed to obtain a clear image in which the entire spread surface is in focus. Reading time can be shortened.

  Further, in the first embodiment, the image reading device 1 includes the depth of field setting unit 150. The depth of field setting unit 150 sets the depth of field DOF 2 in accordance with the desired resolution. Based on the depth of field DOF2 set by the depth of field setting unit 150, the height difference determination unit 140 determines whether the height difference DOE2 is within the depth of field DOF2.

  Here, the higher the resolution, the higher the spatial frequency can be reproduced, but the smaller the depth of field. Therefore, if the desired resolution is low, it is possible to increase the depth of field. Therefore, by setting the depth of field according to the desired resolution, it is possible to obtain an image of the desired resolution.

  Further, in the first embodiment, the image reading apparatus 1 includes the number of times of reading determination unit 160. The reading number determination unit 160 determines the number of readings in multiple reading based on the height difference DOE2. The second image reading unit 71 performs a plurality of readings based on the number of readings determined by the number-of-readings determining unit 160.

  By doing this, it is possible to acquire a clear image in which the entire spread surface is in focus with the minimum number of readings.

  In the first embodiment, when the number of times of reading in the multiple reading is two, the second image reading unit 71 performs the first reading by scanning from the far side to the near side in the depth direction, and the first reading The second reading is performed by scanning from the near side to the far side in the depth direction, starting from the end position of f.

  By doing this, it is possible to shorten the idle time between the first reading and the second reading, so it is possible to acquire an image of the entire surface of the spread surface twice with the minimum reading time.

  Further, in the first embodiment, the second image reading unit 71 obtains a plurality of images having different magnifications. The synthesizing unit 170 performs magnification adjustment to adjust the acquired plurality of images to the same magnification, and synthesizes the in-focus areas of the plurality of images after the magnification adjustment.

  By doing this, even when a plurality of images having different magnifications are acquired by performing a plurality of readings, it is possible to acquire a clear image having the same magnification over the entire spread surface.

Example 2
<Configuration of Image Reading Device>
In the first embodiment, the case where the first image reading unit 61 and the second image reading unit 71 are line sensors has been described. On the other hand, in the second embodiment, the case where the first image reading unit 61 and the second image reading unit 71 are area sensors will be described. That is, in the second embodiment, the first image reading unit 61 and the second image reading unit 71 have, for example, a plurality of light receiving elements linearly arranged along the width direction (X direction) in the depth direction (Y direction) It is a rectangular sensor formed by being arranged in two or more rows. Since the first image reading unit 61 is an area sensor that forms the reading area S1F, it is possible to read an image of the entire surface of the facing surface P1 of the facing medium SM by one imaging. Further, since the second image reading unit 71 is an area sensor that forms the reading area S2F, it is possible to read an image of the entire surface of the spread surface P2 of the spread medium SM by one imaging.

  Further, in the second embodiment, since the first image reading unit 61 is an area sensor, the irradiation range of the first illumination 81 is rectangular in the horizontal plane, and is larger than the reading area S1FA in both the width direction and the depth direction. large. Further, since the second image reading unit 71 is an area sensor, the irradiation range of the second illumination 82 is rectangular in the horizontal plane, and is larger than the reading area S2FA in both the width direction and the depth direction.

  In the second embodiment, the first image reading unit 61 and the second image reading unit 71 do not move, and the first illumination 81 and the second illumination 82 do not rotate. Therefore, the image reading device 1 of the second embodiment does not have the first carrier moving mechanism 63, the first mirror rotation mechanism 65, the first illumination rotation mechanism 83, and the first mechanism control unit 103. Further, the image reading apparatus 1 of the second embodiment does not have the second carrier moving mechanism 73, the second mirror rotation mechanism 75, the second illumination rotation mechanism 84, and the second mechanism control unit 110.

<Operation of Image Reading Device>
FIG. 25 is a diagram for explaining the operation of the image reading apparatus according to the second embodiment. Here, since the operation on the first mounting surface 24 and the operation on the second mounting surface 25 are the same, the operation on the second mounting surface 25 will be described below. The description of the operation is omitted. Further, the reading number determining unit 160 obtains positions B1 and B2 corresponding to the height of the division boundary DB in the spread plane P2 as division boundary positions, and outputs the calculated division boundary positions B1 and B2 to the image reading control unit 101. The operation up to this point is the same as the operation in the first embodiment, so the description will be omitted. In the following, as an example, the case where the number of times of reading K is determined to be twice (K = 2) will be described.

  The image reading control unit 101 changes the in-focus area by adjusting the focal length of the lens 76 between the first reading and the second reading as follows.

  As shown in FIG. 25 (a1), the image reading control unit 101 sets the lens so that the position SP1 (see FIG. 19 (a1)) existing in the focusing area FA1 becomes the focus position FP1 at the first reading. Adjust the focal length of 76 to “L1”. Therefore, in the first reading, as shown in FIG. 25A2, an image in focus at a position at a height higher than the division boundary DB can be obtained in the spread plane P2. FIG. 25 (a2) shows, as an example, the case where the left half of the spread plane P2 is the focusing area FA1.

  On the other hand, as shown in FIG. 25 (b1), the image reading control unit 101 causes the position SP2 (see FIG. 19 (b1)) existing in the focusing area FA2 to be the focus position FP2 at the second reading. Thus, the focal length of the lens 76 is adjusted to “L2”. L2> L1. Therefore, in the second reading, as shown in FIG. 25 (b 2), in the spread plane P 2, an image in focus at a position at a height less than the division boundary DB is obtained. FIG. 25 (b 2) shows, as an example, the case where the right half of the spread plane P 2 is the focusing area FA 2.

  Therefore, by combining the left half image of the image obtained in the first reading and the right half image obtained in the second reading, it is possible to obtain an image in focus on the entire spread surface P2. it can.

  Therefore, as shown in FIGS. 25 (a2) and 25 (a3), the combining unit 170 sets the region where the contrast is greater than or equal to the threshold TH from the image of the entire spread surface P2 obtained in the first reading. Extract an image of the contrast region). This is because it is possible to determine that the high contrast area is an area in focus. Therefore, here, the image of the in-focus area FA1 (that is, the left half image) is extracted from the image of the entire facing plane P2.

  Further, as shown in FIGS. 25 (b2) and 25 (b3), the combining unit 170 extracts the image of the high contrast area from the image of the entire facing surface P2 obtained by the second reading. Therefore, here, the image of the in-focus area FA2 (that is, the right half image) is extracted from the image of the entire surface of the spread plane P2.

  Then, as illustrated in FIG. 25C, the combining unit 170 can obtain an image in focus on the entire facing plane P2 by combining the left half image and the right half image.

  As described above, in the second embodiment, as in the first embodiment, when the height difference DOE 2 is within the depth of field DOF 2, the second image reading unit 71 sets the entire area of the facing surface P 2 as the in-focus region. A single scan is performed to read the scanned image once. On the other hand, when the height difference DOE2 exceeds the depth of field DOF2, the second image reading unit 71 performs a plurality of readings for reading a plurality of images having different in-focus areas on the spread surface P2. The combining unit 170 combines the in-focus areas of the plurality of images obtained by the plurality of readings by the second image reading unit 71.

  Further, in the second embodiment, the combining unit 170 combines the in-focus areas of the plurality of images based on the contrasts of the plurality of acquired images.

  In this way, even when a plurality of images are acquired by changing the focal length of the lens, it is possible to acquire a clear image in which the entire surface of the spread surface is in focus.

[Example 3]
The third embodiment is different from the first embodiment in the method of estimating the heights of the facing surfaces P1 and P2. The differences from the first embodiment will be described below.

<Structure of Image Reading Device>
FIG. 26 is a schematic view (perspective view) of the image reading apparatus of the third embodiment. 26, the image reading apparatus 400 has cameras CA1 and CA2 in place of the first linear light imaging camera 231 and the second linear light imaging camera 232 of the first embodiment. Further, the image reading apparatus 400 does not have the first linear light irradiation unit 211, the first irradiation unit rotation mechanism 221, the second linear light irradiation unit 212, and the second irradiation unit rotation mechanism 222 according to the first embodiment. .

  As shown in FIG. 26, the camera CA1 is disposed on the side of the first reading unit 6, and the camera CA2 is disposed on the side of the second reading unit 7. Each of the cameras CA1 and CA2 sets the entire surface of the mounting surfaces 24 and 25 as a shooting range.

<Operation of Image Reading Device>
27 and 28 are diagrams for explaining the operation of the image reading apparatus of the third embodiment.

  Each of the cameras CA1 and CA2 can capture the entire surface of the facing surfaces P1 and P2 of the facing medium SM because the entire surface of the mounting surfaces 24 and 25 is the imaging range.

  In FIG. 28, first, the height difference detection unit 130 acquires an image PC1 captured by the camera CA1 and an image PC2 captured by the camera CA2.

  Next, the height difference detection unit 130 detects the corresponding points CP based on the feature points of the image PC1 and the feature points of the image PC2. Note that the height difference detection unit 130 may detect the corresponding point CP based on the change in brightness instead of the feature point.

  The height difference detection unit 130 then uses the well-known triangular distance measurement method based on the positional relationship between the camera CA1, the camera CA2, and the corresponding point CP to set the heights of the spread planes P1 and P2 at the corresponding point CP. Estimate the The height difference detection unit 130 detects a plurality of corresponding points CP, and estimates the heights of the spread planes P1 and P2 at each of the plurality of corresponding points CP.

Example 4
The fourth embodiment is different from the first and third embodiments in the method of estimating the height of the facing surfaces P1 and P2. The differences from the first and third embodiments will be described below.

<Structure of Image Reading Device>
FIG. 29 is a schematic view (perspective view) of the image reading apparatus of the fourth embodiment. In FIG. 29, the image reading apparatus 500 has a camera CA instead of the first linear light imaging camera 231 and the second linear light imaging camera 232 of the first embodiment. The image reading device 500 also has a projector PJ. Further, the image reading apparatus 500 does not have the first linear light irradiation unit 211, the first irradiation unit rotation mechanism 221, the second linear light irradiation unit 212, and the second irradiation unit rotation mechanism 222 according to the first embodiment. .

  As shown in FIG. 29, the camera CA is disposed on the front of the arm 3. The projector PJ is disposed on the upper surface of the arm 3. The camera CA takes the entire surface of the mounting surfaces 24 and 25 as the imaging range. Further, the projection range of the projector PJ is larger than the area of the mounting surfaces 24 and 25.

<Operation of Image Reading Device>
FIGS. 30 and 31 are diagrams for explaining the operation of the image reading apparatus of the fourth embodiment. FIG. 30 shows an operation example 1 and FIG. 31 shows an operation example 2.

<Operation Example 1: FIG. 30>
In FIG. 30, since the camera CA takes the entire surface of the mounting surfaces 24 and 25 as the imaging range, it can capture the entire surface of the facing surfaces P1 and P2 of the facing medium SM. The projector PJ projects the mesh light on the entire surfaces of the facing surfaces P1 and P2.

  First, the camera CA captures an image of the entire surface of the spread planes P1, P2 including the mesh light projected onto the entire surfaces of the spread planes P1, P2.

  Next, the height difference detection unit 130 extracts mesh light from the image based on the gradation data of the image captured by the camera CA.

  Next, the height difference detection unit 130 separates the extracted mesh light into line light.

  Then, the height difference detection unit 130 estimates the height of each point on the spread planes P1 and P2 by calculating a known plane equation based on the separated line lights.

<Operation Example 2: FIG. 31>
In FIG. 31, since the camera CA takes the entire surface of the mounting surfaces 24 and 25 as the imaging range, the camera CA can capture the entire surface of the facing surfaces P1 and P2 of the facing medium SM. The projector PJ projects a fringe pattern on the entire surface of the facing surfaces P1 and P2.

  First, the camera CA captures a stripe pattern projected on the entire surfaces of the facing surfaces P1 and P2.

  Next, the height difference detection unit 130 calculates the phase of each pixel of the captured fringe pattern.

  Then, the height difference detection unit 130 estimates the height of each point on the spread planes P1 and P2 based on the calculated phase.

[Other embodiments]
[1] In the first embodiment, the in-focus area FA1 is an area from the division boundary DB upward to the depth of field DOF2, and the in-focus area FA2 from the division boundary DB to the depth of field DOF2 in the vertical direction Region.

  However, the starting point of the in-focus area may be “division boundary DB ± α” instead of the division boundary DB. That is, the in-focus area FA1 is an area from the “division boundary DB-α” to the upper side in the vertical direction to the depth of field DOF2, and the in-focus area FA2 from the “division boundary DB + α” to the depth of field DOF2 in the vertical direction It is good as the area of By doing this, an overlapping area FA0 is formed in which a part of the focusing area FA1 and a part of the focusing area FA2 overlap with each other. The combining unit 170 is configured such that the image of the overlap area FA0 included in the right half image after magnification adjustment and the image of the overlap area FA0 included in the left half image after magnification adjustment in FIG. It is good to combine the image and the left half image.

  When the start point of the in-focus area is set as “division boundary DB ± α”, the reading number determination unit 160 determines the minimum M of the conditions satisfying “DOF1 × M ≧ DOE1 + α (M is an integer of 2 or more)”. Is determined as the number of times of reading in the multiple reading by the first reading unit 6, and the smallest K satisfying the condition of "DOF2.times.K.gtoreq.DOE2 + .alpha. (K is an integer of 2 or more)" in the multiple reading in the second reading unit 7 It is good to decide on the number of readings.

  [2] Also in the second embodiment, the starting point of the in-focus area may be “division boundary DB ± α” instead of the division boundary DB. In the second embodiment, in the case where the start point of the in-focus area is “division boundary DB ± α”, the combining unit 170 generates the image of the overlapping area FA0 included in the left half image and the right half image in FIG. It is preferable to combine the images in the high contrast area by overlapping the images in the included overlapping area FA0.

  [3] The upper limit may be set to the number of readings determined by the number of readings determining unit 160. When the determined number of times of reading exceeds the upper limit value, for example, the number of times of reading determination unit 160 may notify the external device 300 of an error via the communication unit 107.

  [4] Each process in the above description of the control unit 10 may be realized by causing a processor included in the image reading device 1, 400, 500 to execute a program corresponding to each process. For example, a program corresponding to each process in the above description may be stored in a memory included in the image reading apparatus 1, 400, 500, and each program may be read from the memory and executed by a processor. Each program may not necessarily be stored in advance in the memory. That is, for example, each program is recorded in advance on a portable recording medium such as a magnetic disk, an optical disk, an IC card, a memory card, etc. connectable to the image reading device 1, 400, 500, and each program is read from the image reading device 1, 400 , 500 may be read from the recording medium and executed. Further, for example, each program is stored in a computer or a server connected to the image reading device 1, 400, 500 wirelessly or by wire via the Internet, LAN, wireless LAN or the like, and each program is stored in the image reading device 1, 400, It may be read out to a processor of 500 and executed.

1,400,500 image reader 10 control unit
101 image reading control unit 130 height difference detection unit 140 height difference determination unit 150 depth of field setting unit 160 reading number determination unit 170 combining unit

Claims (8)

A detection unit that detects a height difference in the spread surface of the binding medium placed on the placement surface;
A determination unit that determines whether the height difference is within a predetermined depth of field;
When the height difference is within the predetermined depth of field based on the determination result of the determination unit, a single reading is performed to read an image in which the entire area of the spread surface is in the in-focus area. And when the height difference exceeds the predetermined depth of field, the plurality of images having different in-focus areas in the spread plane, the plurality of images each being an image of the entire spread plane Reading unit for performing multiple readings,
A combining unit that combines a plurality of in- focus areas that are a part of each of the plurality of images obtained by the plurality of readings;
An image reading apparatus comprising: And a setting unit configured to set the predetermined depth of field in accordance with a desired resolution.
The determination unit determines whether the height difference is within the predetermined depth of field based on the predetermined depth of field set by the setting unit.
The image reading apparatus according to claim 1. The information processing apparatus further comprises a determination unit that determines the number of readings in the plurality of readings based on the height difference,
The reading unit performs the plurality of readings based on the number of readings determined by the determining unit.
The image reading apparatus according to claim 1. When the number of times of reading in the multiple reading is two, the reading unit performs a first reading by scanning in a first direction, and the first direction starts from an end position of the first reading. Make a second reading by scanning in the second direction opposite to
The image reading apparatus according to any one of claims 1 to 3. The reading unit obtains the plurality of images different in magnification from one another.
The combining unit performs magnification adjustment to adjust the plurality of images to the same magnification, and combines the focusing regions with each other in the plurality of images after the magnification adjustment.
The image reading apparatus according to any one of claims 1 to 4. The combining unit combines the in-focus areas with each other in the plurality of images based on the contrast of the plurality of images.
The image reading apparatus according to any one of claims 1 to 4. Detecting the height difference in the spread surface of the binding medium placed on the placement surface;
Determining whether the height difference is within a predetermined depth of field;
When the height difference is within the predetermined depth of field based on the result of the determination, the single reading is performed while reading the image with the entire area of the spread surface as the in-focus area while the height is low. When the difference exceeds the predetermined depth of field , a plurality of readings are performed to read a plurality of images in which focusing regions are different from each other on the spread surface , each being an image of the entire surface of the spread surface Do,
Combining the plurality of in-focus areas that are a part of each of the plurality of images obtained by the plurality of readings;
Image reading method. It is determined whether or not the height difference in the spread surface of the binding medium placed on the placement surface is within a predetermined depth of field,
Based on the result of the determination, when the height difference is within the predetermined depth of field, the reading unit is caused to perform a single reading of an image in which the entire area of the spread surface is the in-focus area. In the case where the height difference exceeds the predetermined depth of field, the plurality of images having different in-focus areas in the spread surface, and each of which is an image of the entire surface of the spread surface Make the reading unit perform multiple readings,
Combining the plurality of in-focus areas that are a part of each of the plurality of images obtained by the plurality of readings;
An image reading program for causing a processor to execute a process.

Images